Conserve angular momentum as the moment of inertia changes — compute the new angular velocity of a figure skater, collapsing system, or any spinning body when its mass distribution is altered.
| Item | Formula / Note | Source / Standard |
|---|---|---|
| Angular momentum conservation | I₁ω₁ = I₂ω₂ | Newton 1687 / Euler rigid-body mechanics |
| Classic example | Ice skater spins faster pulling arms in | Classic demonstration of angular momentum conservation |